Publishing her annual report as Britain’s chief medical officer last week, Dame Sally Davies, warned manufacturers to “ramp up” attempts to reduce the amount of added sugar in food and drink — saying a “sugar tax” may be needed.

She also expressed concern about the wider effects of alcoholic drinks on health, partly because they tend to contain high calorie levels.

“The average quantity of alcohol consumed per person in the UK remains far higher than 50 years ago,” her report stated. “Excess alcohol consumption is associated with cardiovascular disease, cancers of the digestive organs, breast cancer, and suicide.”

An analysis of sugar levels in cider, sherry and spirits found that some drinks contained as many as five teaspoons of sugar in a single serving. By contrast wines and beer contained significantly smaller quantities.

Campaigners and nutritionists said the study showed how alcohol contained “hidden” sugars which could contribute to a series of health problems.

Aseem Malhotra, a cardiologist and science director of Action on Sugar, a campaign group, said: “The amount of sugar in some of these alcoholic drinks is really quite astonishing.

“I enjoy the occasional drink as much as anyone else but it is clearly better to choose the option with the least amount of sugar as the evidence for added sugar being the number one health villain in the diet grows ever stronger.

“Evidence reveals that a moderate amount of red wine, which is comparatively low in sugar, may actually protect against cardiovascular disease and this is my drink of choice.”

Unlike with packaged food products and soft drinks, manufacturers are not required to include information about the ingredients of most alcoholic drinks on labels, meaning shoppers cannot see how much sugar is contained in each drink.

However, lab tests carried out by experts for this newspaper revealed the total amounts of sugar in a selection of 12 different drinks sold by major supermarkets as well as in bars and other shops.

The drink with the highest concentration of sugar was Baileys Irish Cream, which was found to contain 19.5g of the ingredient – around five teaspoons – per 100ml. This amounts to 5g – slightly more than one teaspoon – of sugar per 25ml measure.

A sherry contained the second highest concentration of sugar. Croft Original, was found to have 9.5g, or two teaspoons, in each 100ml glass.

Bulmers Original, a cider, contained 20.5g of sugar, or five teaspoons, in a 568ml bottle, which is the same size as a pint.

By contrast, among the wines, beers and champagne analysed in all but one of the cases each glass or bottle contained less than a teaspoon of sugar.

On Monday the World Health Organisation closes a consultation on new draft guidance which retains its current formal recommendation that no more than 10 per cent of an individual’s daily calories should come from added sugar – the equivalent of 12 “level” teaspoons for the average adult (one level teaspoon equates to around 4g).

However, its proposed guidelines state that a further reduction to 5 per cent – around six teaspoons – “would have additional benefits”. A senior WHO official described the target as the “ideal” limit for which people should now aim.

The limits apply to “free” sugar, which is any sugar that is added to foods by the manufacturer, plus that naturally present in honey, syrups, and fruit juices. It does not include sugar naturally present in milk or whole fruit and vegetables.

The World Health Organisation’s announcement came after its experts considered a report by scientists at Newcastle University which said the lower threshold is needed to reduce tooth decay.

Paula Moynihan, professor of nutrition at the university, who led the study, said all the sugar found in the drinks would be “free sugars” so would contribute to the WHO’s thresholds.

“Many alcoholic drinks contain hidden sugars,” she added. “So if you do drink, opting for drier varieties of drinks such as wine and cider, and mixing spirits with sugar-free as opposed to standard mixers will help limit sugars intake.

“Drinking within sensible limits also will help avoid consuming too much sugars from these sources.”

Jeremy Rockett, marketing director of Gonzales Byass, which produces Croft Sherry, said although it was a “sweet drink”, people would generally only consume a single glass, compared to the larger quantities of soft drinks that they might consume in a single sitting.

“If people want to have a drier sherry they can,” he added.

A spokesman for the Wine and Spirit Trade Association said: "As the research shows most alcoholic drinks contain low levels of sugar. Calorie labelling for alcohol is not mandatory under European law, but the industry is committed to ensuring consumers are aware of this information through its funding of Drinkaware, which promotes responsible drinking and includes calorie information on its website."